so I just need 0.01 CLAM for example and I'm good to go? or are my chances increased to process a block the larger my stash?
Your chance of staking per unit time is proportional to the size of your stash, yes.
If you have 1000 CLAMs you will stake 1 CLAM about once per day on average.
If you have 0.01 CLAMs you will stake 1 CLAM about every 100,000 days (or 274 years) on average although you might get lucky and stake on your first day of trying.